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Unified Medical Language System (UMLS)

UMLS Vocabularies

NCI_UCUM (Unified Code for Units of Measure) - Synopsis

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The Unified Code for Units of Measure (UCUM) is produced and maintained by the Regenstrief Institute, Inc., and the UCUM Organization.

UCUM is intended to facilitate unambiguous communication and interpretation of the meaning of units from one computer system to another.

NCI_UCUM is the terminology for the Unified Code for Units of Measure, a code system for all units of measures used in international science, engineering, and business.

UCUM is employed by standards organizations such as Digital Imaging and Communications in Medicine (DICOM), Health Level 7 International (HL7), and Open Geospatial Consortium in their applications such as Web Map Service (WMS) and Geography Markup Language (GML).

Metathesaurus Update Frequency
UCUM is updated annually as part of the NCI Thesaurus in the Metathesaurus.

Sites Consulted

  1. Schadow, Gunther, McDonald, Clement J. The Unified Code for Units of Measure [Internet]. Indianapolis, (IN): Regenstrief Institute, Inc.; c1999-2013 [cited 2014 Dec 09]. Available from: Jointly published with the UCUM Organization.
  2. CBMI: Center for Biomedical Informatics. Indianapolis (IN): Regenstrief Institute, c2014. Reference Standards; [cited 2014 Dec 08]. Available from: